Networking devices that run according to a policy, or constraints, must conform to the policy or they will not be allowed to transmit within the network. The policy usually controls the devices in order to prevent any collisions with other radio devices or networks. The other networks are known as “non-cooperative” (NC) and could interfere with the radio device. Further, the radio device seeks not to transmit to cause interference, but seeks to avoid it.
Policies, such as those promulgated by the government, are in a language spoken or read by people, such as English or Spanish. Manufacturers or other entities assemble the radio at a location and ship it to a user.
A conventional radio may employ a prevention mode to eliminate security threats implied by policies. Regulators, such as government officials, define fixed requirements for building an application-specific radio device. Manufacturers design products based on their interpretation of the requirements, i.e. policies, and prove to regulators that the built radio satisfies the requirements in order for the radio device to be classified as “certified.”
After all this, a user or operator can purchase a radio device. Although the radio device may be configurable, the configuration options are limited as majority of the features are “locked” prior to the certification process.
Should the user decide to change the application of her radio devices or travel to a location having different policies, the user must take it back to the manufacturer to have the radio modified and re-certified. Otherwise, anyone could modify the software on the radio and security breaches and tampering would result if the radio fell into the wrong hands.
Smart software-defined radio devices (SDRs) offer tremendous performance and operational benefits over current radios. The benefits include the ability to employ dynamic spectrum access procedures, to tailor the system design to a user's unique circumstances and to remotely configure and control networks.
Additionally, a unique aspect of SDRs is their radically different approach from currently established principles of spectrum access. These principles impact many stakeholders. A stakeholder may be any entity, person, company, government agency and the like that have an interest in spectrum availability for a particular band or frequency. For example, users and operators may pool spectra together to improve spectrum access, lease spectrum or use spectrum available to a second market. Actors, such as owners, users and regulators, desire an assurance that the SDRs will not interfere with current spectrum users. Although the actors might be considered the same for any wireless network, a difference with SDRs is that each actor can influence the design, implementation, deployment and performance of a radio.
One drawback to SDRs involves the complexity of their adaptive software. Adaptive software can change its operation mode throughout the life of the device. Verification of all the states of a SDR may be difficult or unfeasible. Further, a SDR may operate in numerous bands during its lifetime. For each band, the software in the SDR may need to emulate different processes, and the processes may need to change and reconfigure dynamically.
These advantages and problems apply to any software-defined device that uses policy-based control. As software becomes more integrated into everyday devices, the control of the device will be driven by the policies and constraints implemented by the software. Instead of hardware changes, modifications and updates may be realized by downloading new policy updates to the device. For example, a software program on a processor may control a coffee maker. A policy constraining the coffee maker could be not heating the water above a certain temperature, such as 100 degrees Celsius, for safety reasons. Thus, the coffee maker will not allow its temperature to rise above that limit. If the limit changes, however, the coffee maker will have to be taken back to the manufacturer or replaced. If the user chooses to not update the limit, then warranties or indemnities may cease to apply for the coffee maker's usage.